Your starter for ten is to identify the speaker - "My men are ready to go on my orders. If there is one more incident on this street, it will explode. If these thugs draw weapons, my men will do likewise" - was it a chief constable, a Mafia boss, or an inner city gang leader?

The answer is, in fact, none of the above. It was a 39-year old man from a small Derbyshire village who was being interviewed on television about the baseball-bat-wielding posse he had organised to protect local property from the depredations of criminals.

With sinking public confidence in the abilities of the police and courts to deal with endemic crime, there has been a rise of organised self-help groups. What began, though, as a phenomenon of marginal groups variously portrayed as heroic or barbaric has now metamorphosed into a part of the criminal justice system. Last month the president of the Association of Chief Police Officers (ACPO) predicted that every police force in Britain would soon have civilian patrols on the streets.

Recently in Blackpool, at a fringe meeting of the Police Federation Conference, a very important debate took place about the future of law and order enforcement in Britain. The key question was whether civilian patrols were a desirable addition to the streets, parks, shopping malls and residential estates of Britain.

Home Secretary Jack Straw has given approval for these developments, and John Newing, the chief constable of Derbyshire and president of ACPO, foresees a large-scale expansion of civilian "neighbourhood wardens" in the near future.

Writing for Police Review, Mr Newing has suggested that the new patrols could deal with "minor disagreements, disputes over noise, children knocking over rubbish bins, uncontrolled pets, minor vandalism and a whole host of incivilities".

Each year, though, there are half a dozen killings and suicides, many arson attacks, and thousands of assaults following disputes between neighbours about noise. In the past five years 19 people have been killed as a result of such disputes. The trouble with portioning off noisy neighbour disputes, the obstreperous conduct of young people, and "incivilities", for civilian patrols, is that these things often escalate unless dealt with by people who are professionally accountable for what happens.

With all their training and accountability, the police still get things wrong from time to time - often enough for us to have grounds for deep anxiety about the consequences of leaving it all to what would doubtless sometimes be a vigilante or a busy-body "dressed in a little brief authority".

The new schemes may offer government a no-cost extension of police patrols, and present an attractive area of exploitation for the private security industry (currently employing about a quarter of a million people in the UK) but they will probably cause more problems than they will solve.

Troublemakers are unlikely to be cowed into submission and public libraries as a result of the patrols. But while librarians will not enjoy an upturn in their work as a result of the patrols, lawyers specialising in civil liberties, assault and human rights probably will.

In one way, the new patrolling civilian wardens will represent a return to the ancient system to which modern policing can trace its ancestry. As the historian Clive Emsley has observed, the constable (a Norman term) arose from an earlier Saxon tradition of collective responsibility when families were grouped in tens and made responsible for each other's good behaviour

Medieval constables, originally appointed by their communities, only later came to acquire duties as agents for the manor and, after that, the state. Watchmen, Professor Emsley points out, were, similarly, at first recruited by and from local urban dwellers but later, under Royal writ, became obligatory appointments.

Technically, the task of the new watches will be to help quell potentially criminal situations. In practice, though, there is every likelihood that the enthusiasm of those on the plebeian patrols will often spill over into vigilantism, especially on the poorer estates.

This is because the real concern of many people involved in street justice is what one expert has called "the primary rules of law themselves, rather than a failure of police and judiciary to uphold existing legislation". People who don't want a serial car thief or burglar to "get off" under the law with another caution or community sentence will, as local law "officers" feel more justified in delivering a dose of people's justice.

Ray Abrahams, a Cambridge University social anthropologist, has made extensive studies of vigilante behaviour around the world. He notes that vigilantism is rarely simply a popular response to the failure of due legal process to deal with crime. Sometimes the vigilantes have other agendas. In Britain, for example, the centuries-old "rough music" (the infliction of physical abuse to the accompaniment of a cacophony of noises from villagers) was often directed at culprits of legally non-indictable behaviour like seduction and domestic violence.

The opportunity to enforce a slightly alternative law and order agenda must present a temptation to many prospective recruits to the new patrols who have certain ideas about, say, the gay community and members of ethnic minorities. Certainly, for Noel Pemberton Billing, the British politician who established the Vigilantes' Society during the First World War, "foreigners, traitors, homosexuals and sadists" appear to have all been part of the same problem.

Peter Gammon, president of the Superintendents Association, has said that the introduction of under-trained patrols hired by local authorities will be an expensive way to make no appreciable difference to crime rates.

"We are already struggling to regain the trust of parts of the community after the Macpherson report into the Stephen Lawrence case," he says. "Neighbourhood warden patrols will, paradoxically, be more expensive than police services, and will further distance police officers from the communities they serve.".

If private patrols are introduced perhaps we should hope that their "performance indicators" are the same of those of the Suffolk Constabulary earlier this century. Admiring a clock on the mantelpiece of a relative recently, I asked my host about it and was told it had been awarded to her father, a police sergeant from Ipswich.

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